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95 lines
No EOL
3.7 KiB
Text
95 lines
No EOL
3.7 KiB
Text
@startuml grin-transaction
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title
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**Current Grin Tranaction Workflow**
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Accurate as of Feb 12th, 2018 - Master branch only
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end title
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actor "Sender" as sender
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actor "Recipient" as recipient
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entity "Grin Node" as grin_node
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== Phase 1 - Sender Initiation ==
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note left of sender
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1: Create Transaction **UUID** (for reference and maintaining correct state)
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2: Set **lock_height** for transaction kernel (current chain height)
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3: Select **inputs** using desired selection strategy
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4: Create **change_output**
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5: Select blinding factor for **change_output**
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end note
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sender -> sender: Lock **inputs** in wallet
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sender -> sender: Store **change_output** in wallet with status "Unconfirmed"
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note left of sender
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6: Calculate **tx_weight**: MAX(-1 * **num_inputs** + 4 * **num_change_outputs** + 1, 1)
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(+1 covers a single output on the receiver's side)
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7: Calculate **fee**: **tx_weight** * 1_000_000 nG
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8: Calculate total blinding excess sum for all inputs and outputs **xS** (private scalar)
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9: Select a random nonce **kS** (private scalar)
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10: Multiply **xS** and **kS** by generator G to create public curve points **xSG** and **kSG**
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end note
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sender -> recipient: **UUID**, **inputs**, **change_output**, **fee**, **lock_height**, **kSG**, **xSG**
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== Phase 2 - Receiver Initiation ==
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note right of recipient
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1: Check fee against number of **inputs**, **change_outputs** +1 * **receiver_output**)
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2: Create **receiver_output**
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3: Choose random blinding factor for **receiver_output** **xR** (private scalar)
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end note
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recipient -> recipient: Store **receiver_output** in wallet with status "Unconfirmed"
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note right of recipient
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4: Calculate message **M** = **fee | lock_height **
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5: Choose random nonce **kR** (private scalar)
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6: Multiply **xR** and **kR** by generator G to create public curve points **xRG** and **kRG**
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7: Compute Schnorr challenge **e** = Blake2(**M** | **kRG** + **kSG**)
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8: Compute Recipient Schnorr signature **sR** = **kR** + **e** * **xR**
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end note
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alt All Okay
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recipient --> sender: Okay - **UUID**, **sR**, **xRG**, **kRG**
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else Any Failure
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recipient -> recipient: Remove **receiver_output** from wallet
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recipient ->x]: Abort
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recipient --> sender: Error
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sender -> sender: Roll back **inputs** and **change_output**
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[x<- sender: Abort
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end
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== Phase 3 - Sender Confirmation ==
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note left of sender
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1: Calculate message **M** = **fee | lock_height **
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2: Compute Schnorr challenge **e** = Blake2(**M** | **kRG** + **kSG**)
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3: Verify **sR** by verifying **kRG** + **e** * **xRG** = **sRG**
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4: Compute Sender Schnorr signature **sS** = **kS** + **e** * **xS**
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end note
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sender -> recipient: **UUID**, **sS**
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== Phase 4 - Receiver Confirmation ==
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note right of recipient
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1: Verify **sS** by verifying **kSG** + **e** * **xSG** = **sSG**
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2: Calculate final signature **s** = (**sS**+**sR**, **kSG**+**kRG**)
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3: Calculate public key for **s**: **xG** = **xRG** + **xSG**
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3: Verify **s** against excess values in final transaction using **xG**
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4: Create Transaction Kernel Containing:
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Signature **s**
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Public key **xG**
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**fee**
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**lock_height**
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end note
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recipient -> recipient: Create final transaction **tx**
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recipient -> grin_node: Post **tx** to mempool
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grin_node --> recipient: "Ok"
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alt All Okay
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recipient --> sender: "Ok" - **UUID**
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...Await confirmation...
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recipient -> grin_node: Confirm **receiver_output**
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recipient -> recipient: Change status of **reciever_output** to "Confirmed"
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sender -> grin_node: Confirm **change_output**
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sender -> sender: Change status of **inputs** to "Spent"
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sender -> sender: Change status of **change_output** to "Confirmed"
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else Any Error
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recipient -> recipient: Remove **receiver_output** from wallet
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recipient ->x]: Abort
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recipient --> sender: Error
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sender -> sender: Roll back **inputs** and **change_output**
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[x<- sender: Abort
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end
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@enduml |